1. Field of the Invention
The present invention relates to a multimedia information providing method in which various types of data having different data formats can be captured in parallel for a user in cases such as videophone communication, capturing and displaying of Internet information and video data, and capturing of map data for navigation, and to an apparatus for implementing the method.
2. Description of the Related Art
With recent advances in communication technology, enhanced performance of information processors, and the supply of products including the processors at inexpensive prices, various types of information are able to be received in homes or offices. In particular, with recent widespread use and technological progress of cellular phones, in addition to a simple telephone function, the cellular phone has had various types of multimedia transmitting and receiving functions such as a simplified Internet receiving function, a mail transmitting/receiving function, a function in which moving pictures are captured through the Internet and are displayed, a function in which audio data compressed by MP3 or the like is captured and provided for listening, and a videophone function in which, by using a built-in camera, simplified moving pictures are mutually transmitted and received with sound. These functions can easily be used by a user. Also, in offices, various types of multimedia are used, such as widespread use of videoconferencing, data sharing by intranet, and information transmission and reception by e-mail.
The widespread use of cellular phones and an increased amount of various types of communication data indicate that not only a widely-used, known frequency-division-multiple-access method which simply assigns a frequency to each user, but also even a time-division-multiple-access method which performs time division on a single frequency has limitations. In order that more people may be users, there is a code-division-multiple-access (CDMA) method which assigns a spread code to each user. The CDMA method has already been studied in a plurality of countries, and is used in some countries. Also, in Japan, “Wide-band CDMA (W-CDMA)” has been developed for cellular phones. Internationally, the creation of a world standard method plan is in process in the International Telecommunication Union. Since this method enables high speed communication, it is expected that the method as a type of CDMA may mainly be used.
In addition, in recent years, navigation devices have widely been used in vehicles, and in these devices, a large amount of information such as map information and information of various facilities such as restaurants and amusement facilities can be recorded in information recording media such as digital versatile disks (DVDs), along with images. This enables a user to display a desired map in accordance with the movement of the position of the user's vehicle and to drive the vehicle along a guidance path displayed by the navigation device. In this guidance, the user is guided through right and left turns and intersections by using enlarged screens and audio guidance, so that the user can easily and safely drive the vehicle to a destination. Also, by retrieving peripheral facilities, information of stopovers and restaurants can be obtained.
This type of navigation device has also had a communication function. Accordingly, by connecting a cellular phone to the navigation device, various types of driving-related information can be received from an information providing center. Moreover, various types of information can be captured such as the reception of video and audio data, including reception from various Internet sites. In particular, unlike the cellular phone, the navigation device is large in size and has a larger high-definition screen and a relatively high-performance information processor. Thus, it is expected that the navigation device will be essential as an in-vehicle multimedia terminal in the future.
As described above, in a navigation device, the large amount of data stored in a DVD or the like must generally be updated according to necessity because, among the data, map data and facility information are modified year by year. For updating, an upgrade version of the DVD (DVD-ROM) must continually be purchased, and a maintenance fee is also needed. In addition, since a navigation device is expensive, a navigation device having similar level functions is also demanded. In one solution, it is possible that, by using widely-used, known communication technology and a cellular phone, as described above, and disclosing the map and facility information recorded in the DVD, the data can be updated as required, and it is possible that detailed information and video and audio can be distributed. Actually, part of the solution is practiced.
By using the above data distribution method, the user can perform the activities of downloading and displaying a desired map on the screen, setting a destination, transmitting the destination to an information center with present-position data based on a global positioning system, requesting the information center to compute a guidance path, driving the vehicle along the path, and requesting the information center to transmit the map data required for traveling. In addition to this type of system, it is possible that various other types can be implemented. These systems are generically called a “communication navigation system”.
As described above, particularly based on the widespread use of cellular phones and advances in communication technology, it is possible that various types of common communication systems can be used. One of them is a circuit-switching videophone communication system as shown in FIG. 10A. FIG. 10A shows a case in which person A who possesses a portable information terminal 51 having a videophone function formed by a video camera 50 and a communication function is communicating with person B as the wife of person A who is using a cellular phone 54 having a videophone function using a video camera 52. In this case, a communication network 55 employing a W-CDMA method that is expected to be widely used in the future is used, and communication is established by 64-kbps circuit switching.
In addition, as FIG. 10B shows, circuit-switching video delivery is possible. In this video delivery, a W-CDMA communication network 55 similar to that shown in FIG. 10A is used, a content provider 56 is connected to a video delivery server 57 by a cable, and the video delivery server 57 is connected to the W-CDMA communication network 55 by a cable. In response to a video delivery request from a cellular phone 58 linked to the W-CDMA communication network 55, the video delivery server 57 receives pictures provided by the content provider 56. FIG. 10B also shows a case in which a baseball broadcast from the content provider 56 is audiovisually provided to a user by using the cellular phone 58.
As FIG. 11A shows, data communication using the i-mode service as a simplified cellular-phone Internet function, which is becoming popular, has functions similar to those in the case using the Internet, and it is possible that more information can be delivered at higher speed. In the case in FIG. 1A, a content provider 56 linked to an Internet network 60 can deliver various types of multimedia information including video and sound which are stored in an information holder by the Internet network 60, and an i-mode center 61 connected to the Internet network 60 can convert the multimedia information into cellular phone data and can transmit the cellular phone data to a cellular phone 62 through a W-CDMA network 55. In this case, catalog data of a new car which is stored in the content provider 56 is transmitted with video in response to a request from the cellular phone 62.
Moreover, FIG. 11B shows a case in which audio communication between a W-CDMA network 55 and a cellular phone 63 is established and data communication related thereto is also performed. It is expected, as a usage form in the future, that this type of demand will be made in many cases. In these cases, the audio communication is performed by circuit switching, and the data communication is performed by packet switching. Thus, in a common usage form in the future, two links are used to perform the two types of communication.
In the cases shown in FIGS. 10A and 10B, and 11A and 11B, the original functions of the cellular phone are used to perform various types of communication so that various types of information are captured. This is not limited to the cellular phone, but also applies to a navigation device connected to the cellular phone, as described above. Specifically, in FIG. 10A, by using a navigation device having a communication function instead of the portable information terminal 51, connecting a video camera in a predetermined position in the vehicle to the navigation device, and using a hands-free unit or the like, the driver can easily use the navigation device. In addition, reception of delivered video as shown in FIG. 10B, reception of provided multimedia information as shown in FIG. 11A, and communication using two links are similarly possible.
By using the W-CDMA network, which is expected to be widely used in the future, information devices, such as cellular phones, navigation devices, and portable information terminals, can obtain types of multimedia information at any time, as required. This is not limited to mobile devices of the above types. Also, in the case of displaying various types of information on a television screen in an ordinary home by using an ordinary telephone line, a similar function can be used.
In addition, inexpensive flat rates of communication will become widely used, and it is expected that a continuous-link type of usage form will be widely used in which a link to a desired party will be made as required, with connection to a communication network maintained, and in which information capture from a videophone and the Internet can be performed, and data is continuously captured and is displayed as required. Even when a metered rate system is employed in which downloading of specified information is charged depending on the used amount, multimedia information can become very inexpensively used, and widespread use of this usage form is expected.
In the above delivery of multimedia information, for videophone circuit switching as shown in FIG. 10A, the H.324 specifications for real-time multimedia communication is used to perform communication, and when packet switching is used to perform videophone communication, H.323 is used. Also, the HTTP specifications are used to perform i-mode packet-switching data capturing and capturing of streaming information that is audiovisually provided while being downloaded. For downloading and using a map, etc., by using a communication navigation device, the WinSock specifications are used.
As described above, types of multimedia information differ in delivery standard and specification, that is, their protocols differ. Accordingly, for example, in order that the multimedia information may be delivered to a cellular phone or a navigation device, the device must have a function of handling data in accordance with each communication standard and specification. An information delivery server of the related art can only deliver requested data in accordance with a predetermined protocol in response to a request from a client. The client cannot receive and display information from the server which is based on a protocol that the client does not support.
Also, in communication through a server among a plurality of clients, as it is impossible to establish a link between a circuit-switching videophone and a packet-switching videophone, communication is impossible unless the corresponding functions and protocols of the clients match.
In a case in which an information terminal has a function of handling all the types of multimedia information, a built-in information processor must receive the multimedia information by using high speed multi-task processing to switch protocols. For this purpose, a high performance central processing unit (CPU) must be used because a common CPU cannot simultaneously receive real-time data, such as audio and video, and picture data and Web data on the Internet.
FIG. 12 shows a case in which a navigation device having a receiving function adapted for a plurality of protocols is of a communication navigation type that downloads and uses map data. The navigation device uses packet-switching information service by using an i-mode browser in accordance with HTTP. When receiving a circuit-switching real-time videophone call in accordance with H.324 during the i-mode service, the navigation device cannot display the call. A person who sends the call is supplied with information indicating that the other party's device is communicating with another. The person must call again later.
After that, the navigation device in FIG. 12 uses subsequent WinSock communication to capture data of communication navigation for data transmission and reception, and receives streaming video and audio delivered in accordance with HTTP after capturing the data. FIG. 12 also shows a state in which, by using the navigation device, a baseball game broadcast is audiovisually received in the form shown in FIG. 10B. While the navigation device is receiving the data of the broadcast, a state as described above that is unable to receive the videophone call from the wife continues. For each type of multimedia information, the information terminal simply performs processing by switching the protocols in response to a user's information-capturing request. This causes a problem in that the types of multimedia information cannot simultaneously be displayed.